package main

import (
	"fmt"
	"time"
)

func Rt(n int, d int) int {
	if n == 1 {
		return d
	}
	return Rt(n-1, (d)*n)
}
func main() {
	start := time.Now()
	fmt.Println(Rt(10000, 1))
	end := time.Now().Sub(start)
	fmt.Println(end)
}
